{
  "id": "1406.7052",
  "version": "v2",
  "published": "2014-06-27T02:15:18.000Z",
  "updated": "2014-08-23T08:14:11.000Z",
  "title": "MOSFIRE and LDSS3 Spectroscopy for an [OII] Blob at z=1.18: Gas Outflow and Energy Source",
  "authors": [
    "Yuichi Harikane",
    "Masami Ouchi",
    "Suraphong Yuma",
    "Michael Rauch",
    "Kimihiko Nakajima",
    "Yoshiaki Ono"
  ],
  "comment": "14 pages, 8 figures, 4 tables. Accepted for publication in the Astrophysical Journal",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We report our Keck/MOSFIRE and Magellan/LDSS3 spectroscopy for an [OII] Blob, OIIB10, that is a high-$z$ galaxy with spatially extended [OII]$\\lambda\\lambda3726,3729$ emission over 30 kpc recently identified by a Subaru large-area narrowband survey. The systemic redshift of OIIB10 is $z=1.18$ securely determined with [OIII]$\\lambda\\lambda4959,5007$ and H$\\beta$ emission lines. We identify FeII$\\lambda$2587 and MgII$\\lambda\\lambda$2796,2804 absorption lines blueshifted from the systemic redshift by $80\\pm50$ and $260\\pm40$ km s$^{-1}$, respectively, which indicate gas outflow from OIIB10 with the velocity of $\\sim 80-260$ km s$^{-1}$. This outflow velocity is comparable with the escape velocity, $250\\pm140$ km s$^{-1}$, estimated under the assumption of a singular isothermal halo potential profile. Some fraction of the outflowing gas could escape from the halo of OIIB10, suppressing OIIB10's star-formation activity. We estimate a mass loading factor, $\\eta$, that is a ratio of mass outflow rate to star-formation rate, and obtain $\\eta>0.8\\pm 0.1$ which is relatively high compared with low-$z$ starbursts including U/LIRGs and AGNs. The major energy source of the outflow is unclear with the available data. Although no signature of AGN is found in the X-ray data, OIIB10 falls in the AGN/star-forming composite region in the line diagnostic diagrams. It is possible that the outflow is powered by star formation and a type-2 AGN with narrow FWHM emission line widths of $70-130$ km s$^{-1}$. This is the first detailed spectroscopic study of oxygen-line blobs, which includes the analyses of the escape velocity, the mass loading factor, and the presence of an AGN, and a significant step to understanding the nature of oxygen-line blobs and the relation with gas outflow and star-formation quenching at high redshift.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-06-27T02:15:18.000Z",
      "abstract": "We report our Keck/MOSFIRE and Magellan/LDSS3 spectroscopy for an [OII] Blob, OIIB 10, that is a high-$z$ galaxy with spatially extended [OII]$\\lambda\\lambda3726,3729$ emission over 30 kpc recently identified by the Subaru large-area narrowband survey. The systemic redshift of OIIB 10 is $z=1.18$ securely determined with [OIII]$\\lambda\\lambda4959,5007$ and H$\\beta$ emission lines. We identify FeII$\\lambda$2587 and MgII$\\lambda\\lambda$2796,2804 absorption lines blueshifted from the systemic redshift by $80\\pm50$ and $260\\pm40$ km s$^{-1}$, respectively, which indicate gas outflow from OIIB 10 with the velocity of $\\sim 80-260$ km s$^{-1}$. This outflow velocity is comparable with the escape velocity, $250\\pm140$ km s$^{-1}$, estimated under the assumption of a singular isothermal halo potential profile. Some fraction of the outflowing gas could escape from the halo of OIIB 10, suppressing OIIB 10's star-formation activity. We estimate a mass loading factor, $\\eta$, that is a ratio of mass outflow rate to star-formation rate, and obtain $\\eta>0.8\\pm 0.1$ which is relatively high compared with low-$z$ starbursts including U/LIRGs and AGNs. The major energy source of the outflow is unclear with the available data. Although no signature of AGN is found in the X-ray data, OIIB 10 falls in the AGN/star-forming composite region in the line diagnostic diagrams. It is possible that the outflow is powered by star formation and a type-2 AGN with narrow FWHM emission line widths of $70-130$ km s$^{-1}$. This is the first detailed spectroscopic study for oxygen-line blobs, and the first step to understanding the nature of oxygen-line blobs and the relation with gas outflow and star-formation quenching at high redshift.",
      "comment": "14 pages, 8 figures, 4 tables, submitted to ApJ",
      "journal": null,
      "doi": null
    },
    {
      "version": "v2",
      "updated": "2014-08-23T08:14:11.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "gas outflow",
      "energy source",
      "ldss3 spectroscopy",
      "oiib 10s star-formation activity",
      "isothermal halo potential profile"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/794/2/129",
      "journal": "The Astrophysical Journal",
      "year": 2014,
      "month": "Oct",
      "volume": 794,
      "number": 2,
      "pages": 129
    },
    "note": {
      "typesetting": "TeX",
      "pages": 14,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1303969,
      "adsabs": "2014ApJ...794..129H"
    }
  }
}